hopper/nodes/sorter.lua

local S = minetest.get_translator("hopper")
local FS = hopper.translator_escaped

local facedir_to_bottomdir = {
	[0]={x=0, y=-1, z=0},
	{x=0, y=0, z=-1},
	{x=0, y=0, z=1},
	{x=-1, y=0, z=0},
	{x=1, y=0, z=0},
	{x=0, y=1, z=0},
}

local bottomdir = function(facedir)
	return facedir_to_bottomdir[math.floor(facedir/4)]
end

local function get_sorter_formspec(pos)
	local spos = hopper.get_string_pos(pos)

	local filter_all = minetest.get_meta(pos):get_string("filter_all") == "true"
	local y_displace = 0
	local filter_texture, filter_button_tooltip, filter_body
	if filter_all then
		filter_body = ""
		filter_texture = "hopper_mode_off.png"
		filter_button_tooltip = FS("This sorter is currently set to try sending all items\nin the direction of the arrow. Click this button\nto enable an item-type-specific filter.")
	else
		filter_body = "label[3.7,0;"..FS("Filter").."]list[nodemeta:" .. spos .. ";filter;0,0.5;8,1;]"
		filter_texture = "hopper_mode_on.png"
		filter_button_tooltip = FS("This sorter is currently set to only send items listed\nin the filter list in the direction of the arrow.\nClick this button to set it to try sending all\nitems that way first.")
		y_displace = 1.6
	end

	local formspec =
		"size[8," .. 7 + y_displace .. "]"
		.. hopper.formspec_bg
		.. filter_body
		.. "list[nodemeta:" .. spos .. ";main;3,".. tostring(0.3 + y_displace) .. ";2,2;]"
		.. ("image_button_exit[0,%g;1,1;%s;filter_all;]"):format(y_displace, filter_texture)
		.. "tooltip[filter_all;" .. filter_button_tooltip.. "]"
		.. hopper.get_eject_button_texts(pos, 6, 0.8 + y_displace)
		.. "list[current_player;main;0,".. tostring(2.85 + y_displace) .. ";8,1;]"
		.. "list[current_player;main;0,".. tostring(4.08 + y_displace) .. ";8,3;8]"
		.. "listring[nodemeta:" .. spos .. ";main]"
		.. "listring[current_player;main]"
	return formspec
end


minetest.register_node("hopper:sorter", {
	description = S("Sorter"),
	_doc_items_longdesc = hopper.doc.sorter_long_desc,
	_doc_items_usagehelp = hopper.doc.sorter_usage,
	groups = {cracky = 3},
	sounds = hopper.metal_sounds,
	drawtype = "nodebox",
	paramtype = "light",
	paramtype2 = "facedir",
	tiles = {
			"hopper_bottom_" .. hopper.config.texture_resolution .. ".png",
			"hopper_top_" .. hopper.config.texture_resolution .. ".png",
			"hopper_bottom_" .. hopper.config.texture_resolution .. ".png^hopper_sorter_arrow_" .. hopper.config.texture_resolution .. ".png^[transformFX^hopper_sorter_sub_arrow_" .. hopper.config.texture_resolution .. ".png^[transformFX",
			"hopper_bottom_" .. hopper.config.texture_resolution .. ".png^hopper_sorter_arrow_" .. hopper.config.texture_resolution .. ".png^hopper_sorter_sub_arrow_" .. hopper.config.texture_resolution .. ".png",
			"hopper_top_" .. hopper.config.texture_resolution .. ".png",
			"hopper_bottom_" .. hopper.config.texture_resolution .. ".png^hopper_sorter_arrow_" .. hopper.config.texture_resolution .. ".png",
		},
	node_box = {
		type = "fixed",
		fixed = {
			{-0.3, -0.3, -0.4, 0.3, 0.4, 0.4},
			{-0.2, -0.2, 0.4, 0.2, 0.2, 0.7},
			{-0.2, -0.3, -0.2, 0.2, -0.7, 0.2},
		},
	},

	on_construct = function(pos)
		local meta = minetest.get_meta(pos)
		local inv = meta:get_inventory()
		inv:set_size("main", 2*2)
		inv:set_size("filter", 8)
	end,

	on_place = function(itemstack, placer, pointed_thing, node_name)
		local pos2 = pointed_thing.above

		local returned_stack, success = minetest.item_place_node(itemstack, placer, pointed_thing)
		if success then
			local meta = minetest.get_meta(pos2)
			meta:set_string("placer", placer:get_player_name())
		end
		return returned_stack
	end,

	can_dig = function(pos,player)
		local meta = minetest.get_meta(pos);
		local inv = meta:get_inventory()
		return inv:is_empty("main")
	end,

	on_rightclick = function(pos, node, clicker, itemstack)
		if minetest.is_protected(pos, clicker:get_player_name()) and not minetest.check_player_privs(clicker, "protection_bypass") then
			return
		end
		minetest.show_formspec(clicker:get_player_name(),
			"hopper_formspec:"..minetest.pos_to_string(pos), get_sorter_formspec(pos))
	end,

	allow_metadata_inventory_put = function(pos, listname, index, stack, player)
		if listname == "filter" then
			local inv = minetest.get_inventory({type="node", pos=pos})
			inv:set_stack(listname, index, stack:take_item(1))
			return 0
		end
		return stack:get_count()
	end,

	allow_metadata_inventory_take = function(pos, listname, index, stack, player)
		if listname == "filter" then
			local inv = minetest.get_inventory({type="node", pos=pos})
			inv:set_stack(listname, index, ItemStack(""))
			return 0
		end
		return stack:get_count()
	end,

	allow_metadata_inventory_move = function(pos, from_list, from_index, to_list, to_index, count, player)
		if to_list == "filter" then
			local inv = minetest.get_inventory({type="node", pos=pos})
			local stack_moved = inv:get_stack(from_list, from_index)
			inv:set_stack(to_list, to_index, stack_moved:take_item(1))
			return 0
		elseif from_list == "filter" then
			local inv = minetest.get_inventory({type="node", pos=pos})
			inv:set_stack(from_list, from_index, ItemStack(""))
			return 0
		end
		return count
	end,

	on_metadata_inventory_put = function(pos, listname, index, stack, player)
		hopper.log_inventory(("%s moves stuff to sorter at %s"):format(
			player:get_player_name(), minetest.pos_to_string(pos)))

		local timer = minetest.get_node_timer(pos)
		if not timer:is_started() then
			timer:start(1)
		end
	end,

	on_timer = function(pos, elapsed)
		local meta = minetest.get_meta(pos);
		local inv = meta:get_inventory()

		-- build a filter list
		local filter_items = nil
		if meta:get_string("filter_all") ~= "true" then
			filter_items = {}
			local filter_inv_size = inv:get_size("filter")
			for i = 1, filter_inv_size do
				local stack = inv:get_stack("filter", i)
				local item = stack:get_name()
				if item ~= "" then
					filter_items[item] = true
				end
			end
		end

		local node = minetest.get_node(pos)
		local dir = minetest.facedir_to_dir(node.param2)
		local default_destination_pos = vector.add(pos, dir)
		local default_output_direction = (dir.y == 0) and "side" or "bottom"

		dir = bottomdir(node.param2)
		local filter_destination_pos = vector.add(pos, dir)
		local filter_output_direction = (dir.y == 0) and "side" or "bottom"

		--- returns success? = true/false
		local function try_send_item(output_dir, dst_pos)
			local dst_node = minetest.get_node(dst_pos)
			local registered_inventories = hopper.get_registered(dst_node.name)

			if registered_inventories ~= nil then
				return hopper.send_item_to(pos, dst_pos, dst_node, registered_inventories[output_dir], filter_items)
			end

			return hopper.send_item_to(pos, dst_pos, dst_node, nil, filter_items)
		end

		if not try_send_item(filter_output_direction, filter_destination_pos) then
			-- weren't able to put something in the filter destination, for whatever reason.
			-- Now we can start moving stuff forward to the default.
			try_send_item(default_output_direction, default_destination_pos)
		end

		if not inv:is_empty("main") then
			minetest.get_node_timer(pos):start(1)
		end
	end,
})